The objective of this research project is to improve the storage of human red cells and to learn more about how effective they are, when transfused, for the treatment of clinical hypoxia. The rabbit is our principal model for these studies. Rabbit blood is being stored under a variety of conditions and with various additives and the effects on the metabolism, physiological properties and post-transfusion viability of the red cells are being examined. The organs of rabbits made severely hypoxic by bleeding are being studied to try to find out what metabolic changes are most critical for the survival of the animal. Hypoxic rabbits are being transfused with red cells which have been stored under different conditions to discover how they influence the survival of the animals and reverse certain biochemical changes such as the loss of soluble adenine nucleotides and the elevation of glycolysis.